The thing that bugs me is the chronology. In the Marvel comics of the '60s, they more or less followed real time, or at least came closer than they do now; Peter Parker started out in high school and was going to college within a few years thereafter. And of course they treated their '40s comics as having taken place in the '40s. So it was possible to do Marvels as a period piece spanning the '40s through the '60s and have it hold together. (And in answer to RookieBatman, that was part of the appeal of Ross's photorealistic artwork; that plus the chronology gave the whole thing a sense of reality, of authenticity, like it was a living history.)
But by the '70s and '80s, we were deep into "Marvel time," where the characters barely aged and their past was on a "sliding time scale." Decades passed in the real world while only a few years passed for the characters, and their origins had already been retconned forward in time. So I don't see how this sequel can have quite the same sense of historical authenticity and internal consistency as the original.